LOS ANGELES — For the past few years, the powers that be in college sports have watched nervously as an antitrust lawsuit wends its way through federal court.

O’Bannon vs. NCAA is challenging traditional notions of amateurism, arguing that young athletes should receive more than just scholarships for their role in what has become a multibillion-dollar enterprise.

Yesterday, the case arrived at a crucial fork in the road.

A northern California judge must decide if thousands of current and former college players can join as plaintiffs in what would become a class-action suit.

That could set the stage for a massive judgment, potentially changing the business of Saturday afternoon football games and March Madness.

“It’s a very big deal,” said Michael McCann, a professor at the University of New Hampshire School of Law. “This could be an instrumental lawsuit in terms of reshaping college sports.”

The case, spearheaded by former UCLA basketball player Ed O’Bannon, focuses on the way the NCAA and its business partners profit by using athletes’ names and likenesses in video games, photographs, promotions and, potentially, television broadcasts. The plaintiffs want a cut.

U.S. District Court Judge Claudia Wilken didn’t rule on either the merits of O’Bannon’s case or his demands to turn the case into a class-action lawsuit. It could take weeks, even months, before Wilken rules. Instead, she ordered O’Bannon’s attorneys to revise the lawsuit to fix some legal technicalities, including explicating adding current players to the lawsuit. Attorney Michael Hausfeld said he will file a new lawsuit that includes current players, but will seek to keep their names confidential.

“They are afraid of retaliation,” Hausfeld told the court.

NCAA attorney Greg Curtner is against certifying the lawsuit as a class action, arguing that the claims of thousands of collegiate athletes are too different to be treated the same. For instance, certain athletes bring in more revenue than others and have different legal claims at stake.

The NCAA argues that many of the athletes receive scholarships in exchange for playing sports, and to pay student athletes would ruin amateur athletics. To pay athletes more than that would ruin collegiate sports, the NCAA argues.

College sports leaders say they need the riches derived from football and men’s basketball to support less-popular sports. Big Ten commissioner Jim Delany filed a legal declaration stating that changes to the current system might force his member schools to “downsize the scope, breadth and activity of their athletic programs,” shifting to a model that resembles the smaller, less-glamorous Division III.

But not everyone agrees with such a doomsday prediction.

Some believe there is enough money to spread around, and a longtime critic of college sports wonders if giving athletes a larger share might help curtail what she sees as out-of-control spending on coaching salaries and training facilities.

“The perception that college athletics as we know them would be destroyed is an overreaction,” said Ellen Staurowsky, a sport management professor at Drexel. “This could be a clarifying moment.”

The O’Bannon suit originally focused on the use of former athlete likenesses in video games licensed by the NCAA and sold by EA Sports. The Collegiate Licensing Co., which represents nearly 200 colleges, the Heisman Trophy and the NCAA, was named, too.

“I saw a kid playing a video game that had my likeness, and I thought that was wrong,” said O’Bannon, who now lives in Nevada, working at a car dealership and coaching high-school basketball.

His legal challenge soon broadened, seeking to include current athletes and bringing television into the mix. TV money dwarfs video-game revenue, which has been estimated at less than $10 million a year.